Starter quiz

1. Match these impacts of drought with the correct drought type Starter quiz 1. Widespread failure of agricultural systems Food shortages on seasonal scale Rural economy collapses Rural-urban migration Increased malnutrition and related mortality Humanitarian crisis International aid required A. Meteorological drought 2. Poor yields from crops Irrigation systems start to fail Pasture and livestock productivity declines Rural industries affected Some government aid required B. Hydrological drought C. Agricultural drought 3. Loss of soil moisture Supply of irrigation water declines D. Famine drought 4. Reduced storage in lakes and reservoirs Less water for urban supply – restrictions Poorer water quality Threats to wetlands and wildlife habitats

2. Other anthropological (human) factors to consider: Population increase Increase in wealth Physical causes of drought Summary of human causes of drought: L/O: 1. To evaluate strengths and weaknesses of different drought indices 2. To explain the role Earth’s differential heating, global atmospheric circulation, ITCZ and Coriolis effect in creating naturally drier/wetter areas 3. To consider the role of ENSO (El Nino-Southern Oscillation) in impacting rainfall rates around the world

3. The land area that experiences some level of drought exposure covers about 70% of the total global population, with the most severe drought exposure including 18% of the global population TASK: Describe the global distribution of drought. Figure 1: The global distribution of drought (drought exposure increases with higher deciles)

4. Drought Indices Use your homework to complete this table:

5. Drought Indices Use your homework to complete this table:

6. KEY IDEA:The physical causes of drought can be largely explained by the global atmospheric circulation system …but you need to understand differential heating before you can appreciate the purpose of the GAC

7. At latitudes 40 degrees north and south of equator or above, the outgoing heat radiation from Earth exceeds the incoming heat radiation from the sun WHY?

8. Differential heating Use the information from the videos you watched at home to explain these three images 20% reflected by vegetation and dark soil 10% reflected by ocean water 85-90% reflected by snow Image A Image B Image C

9. Differential heating Use the information from the videos you watched at home to explain these three images 20% reflected by vegetation and dark soil 10% reflected by ocean water 85-90% reflected by snow So the global atmospheric system is caused partly by the amount of heat different parts of the Earth receive… … but also by the Earth’s rotation! Image A Image B Image C

10. So… KEY IDEAthe Global Atmospheric Circulation system redistributes heat through 3 large atmospheric cells

13. Bring this back to physical causes of drought… • The GAC causes natural variability in climate– e.g. weather patterns, jet streams, deserts, prevailing winds are all due to the GAC We will now explore the second physical cause of drought: 2. Long-term susceptibility – brought about by ENSO and climate change associated with global warming (i.e. higher temps = higher evapotranspiration rates)

14. Exam Practice Study Figure 2. Explain how physical and human factors have contributed to the variation in water scarcity shown.(8)